Hot workable phosphor bronze



Patented Sept. 6, 1938 HOT WORKABLE PHOSPHOR BRONZE Richard B. Montgomery, Derby, Conn., assignor to The American Brass Company, Waterbury, Conn., a corporation oLConnecticut No Drawing.

This invention relates to copper-tinlalloys, and more particularly to a phosphor bronze, and has for an object to produce such an alloy which is hot workable and has greater strength and hard- 5 ness. 1 \P This application is a continuation in part of my prior application Serial No. 108,616, filed October 31, 1936.

The so-called phosphor bronzes are alloys of 10 copper and tin deqxidized with phosphorus before pouring or casting the molten metal into suitable molds. In order to make sure the metal is properly deoxidized there is usually sufiicient of the .deozidizer used so that there is a small surplus 15 and a small amount of the deo'xidizer remains in the resulting alloy. In the present alloy, however, suificint phosphorus is added not only to-deoxidize the melt but to have some residual phosphorus alloyed with the metal for the purpose of 20 securing definite physical properties.

The tin bronzes may be cold rolled up to about 12 percent tin content. These bronzes as a rule also maybe hot rolled or worked up to about 2 percent tin content, but the hot rolling or hot" 25 working becomes rapidly impossible as the tin content is increased over 2 percent. I I have found that, with an appreciable amount of phosphorus remaining in the alloy and up to about 1 percent, bythe addition of sufflcient,

- worked with a tin content upto 20 percent. Thus a tin bronze that could not be hot rolled at all 35 canbe-easily hot rolled with additions of phosphorus and iron in the ratio of one to four.

This effect is secured in these copper tin alloys with a tin content of from 2 to 20 percent and balance principally copper, the content'of phos-p 4 phorustbeing from 0.05 percent up to about 1 being hot workable.

' percent, and the content of iron from 0.25 percent to about 5 percenti The content of iron for best results should be at least suflicient so that the 1 ratio of phosphorus to iron is about 1 to 4, or suf U ficient to form the compound FezP. Thus in this alloy suflicient phosphorusis added not only to deoxidize the melt, but to have some residual phosphorus alloyed with the metal for the purpose of securing definite physical properties, and suf- 50 ficient iron isaddedto convert the phosphorus into iron phosphide. l h

It appears that the phosphorus in a phosphor Application November 26, 1937, Serial N0. 176,666

4 Claims. 01. 75-154) bronze when iron is present in amount insufficient to form the compound FezP forms a phosphorustin compound which melts below a suitable hot rolling temperature and thereby further increases the hot shortness of the tin bronzes containing 6 more than 2 percent tin, and making it even more diflicult to hot work. However, it appearsthat with iron present in amountsufiicient to convert all, or substantially all, of the phosphorus into iron phosphideFezP no objectionable phosphorus- 10 tin compound is formed, but the-compound of iron and phosphorus is formed instead, which compound melts considerably above the hot rolling temperature. Uponlcooling this copper-tiniron-phosphorus alloy the iron phosphide crystallizes first from the melt. Thus dispersed throughout the liquid metal, these particles appear to control the crystallization of the copper and tin producing a fine grainflstructure. with littletin segregation. Therefore, it is seen that by having phosphorus and iron present in substantially the above mentioned ratio a phosphor bronze of higher tin content may be produced which can be hot rolled or hot forged, and which due to its superior structure possesses greater strength and hardness than the ordinary phosphor bronze.

It will be appreciated a large number of specific alloys may be made within the ranges of elements noted, but an example of an alloy that hot rolls very nicely has approximately the following proportions, tin 5 percent, iron 05 percent, phosphorus'0.1 percent, and balance copper.

An example of another desirable alloy has approximately 10 percent tin, 1 percent iron, 0.2

percent phosphorus, and balance copper. 36

Having thus set forth the nature of my invention, what I claim is: r

1. An alloy composed of 2%v to 20% tin, from 0.25% to 5% iron; phosphorus from 0.05% up to 1% and balance copper, which is characterized by 40 *2. An alloy composed of 2% to 20% tin, from 0.25%to 5% iron, phosphorus from.0.05% upto 1%, and balance copper, and in which the iron content is at least about four times the 'phosphorus content. k

3. An alloy composed of approximately 5% tin, 0.5% iron; 0.1% phosphorus, and balance copper. 4; An alloy composed of approximately 10% tin,

1% iron, 0.2% phosphorus, and balance copper.

3mm B. MONTGOMERY. 

